Method of treating cellulose textile material



Patented Aug. 19,1941

METHOD OF TREATING OELLULOSE rnxmn MATERIAL Eric Owen Bidgway,Montclair, and William A. Bodenschata, Brooklawn, N. 1., assignors toRidbo laboratories Incorporated, Nutley, N. 1., acorporation of NewJersey A No Drawing. Application August 17, 1939, Serial No. 290,627

8Claims.

This invention relates to methods of treating cellulose and moreparticularly to methods of treating and finishing cellulosic textilefibres.

This application is a continuation in part of our applications SerialNo. 112,984, filed November 27, 1936, and Serial No, 172,152, filedNovember 1, 1937,

The invention contemplates improving the qualities of cellulosic textilefibres. For example, material treated in accordance with the inventionhas an improved appearance, handle, sheerness, increased hot flexinglife, and increased tensile strength both at normal and at hightemperatures, has substantially no shrinkage, resists wrinkling, mildew;and has greater moisture absorption properties and is more receptive todyeing than untreated material.

, textile fibres with a water-soluble copper salt and then with asolution containing ammonium hydroxide and one or more alkali hydroxidesstronger than ammonium hydroxide, such as sodium hydroxide and/orpotassium hydroxide. The concentrations of the water-soluble copper saltand the hydroxides employed are such that only the. lesser celiulosesand other impurities are selectively dissolved and removed, withoutdissolution of the alpha-cellulose and the resultant disintegration ofthe fibre; thereby obtaining accurate control of the reactingingredients at all times. The removal of the impurities has the effectof lessening the diameter of the fibres, and amore sheer fabric isproduced; also there is a tendency to unite the random fibres to thefibre they be' in the form of fabrics, knitted or woven,

yarns, cords, threads, fibres or coverings.

The present invention may be employed for the purpose of securing apattern of contrasting shades of dye simultaneously from the same dyebath. This result may be obtained by printing.

the fabric with one or more of the reagents so that the treatment takesplace-only in local portions. An alternative method is to print thefabric with a "resist" before treatment by. our method, so that thereaction will take place only in those portions where there is nosubstance to resist or inhibit the reaction. In this way, a greatvariety of efiects may be obtained.

Highly satisfactory results have also been obtained in applying theimproved method to fabrics used for insulating purposes, or to thecoverings of vwires used for insulating purposes.

The resultant product is an insulating material of higher dielectricconstant having a reduced diameter. Furthermore, with the removal of theimpurities the cellulosic textile fibres are more porous, thus they maymore readily be impregnated with various coating and impregnating agentssuch as the synthetic resins, varnishes, lacquers, crease-resistingagents, etc., used for the above and other purposes.

In practice a suitable cellulosic textile fibre such as fabrics andyarns, either in the grey or bleached condition, is treated with asolution of bundle through contraction. The treatment of.

' synthetic fibres of cellulose that is. rayon or other regeneratedcellulose, in accordance with this invention adds a very distinct anddefinite appearance and handle which these materials do not otherwiseposes in that. after treatment, they have a "liveness and the lustre issomeany water-soluble copper salt; for example, saltisfactory resultshave been obtained by employing copper sulphate, copper nitrate, copperbromide, or copper chloride. The excess salt solution is then removed inany suitable manner,- such as by centrifuging or squeeze rolls, and thefibre is then led into a solution containing ammonium hydroxide andsodium hydroxide, or ammonium hydroxide and any other alkaline hydroxideor mixture of hydroxides stronger than ammonium hydroxide, such aspotassium hydroxide. The ratio of water-soluble copper salt to cellulosemay be varied, and, likewise, the resultant treatment may be modified,for example, a solution of ammonium hydroxide and a relatively strongsolution of sodium hydroxide may be employed, or a solution containingammonium hydroxide and relatively dilute sodium hydroxide may first beused, and the fibres later passed through a stronger solution of sodiumhydroxide. The preferred concentrations and ratios and their limits willbe fully set forth hereinafter,

By way of example, 'two types of grey cloth .identified as Indian HeadBrown Sheeting and Pequot Heavy Sheeting were treated in accordance withthe method of the present invention. .The materials used were given thecustomary preliminary treatment consisting of treatment in boiling waterfor several hours and then rinsing in clear water, soaking in an aqueoussolution containing an enzyme, for removing starch for four hours at atemperature of 70 C. and then rinsing in clear water, treating in aboiling aqueous solution containing sodium hydroxide (8 grams per litre)and sodium carbonate (1 gram per litre), and then washing, treating withdilute acid and finally rinsing in clear water and dried to constantweight.

The material was then treated in a solution of copper sulphate andthereafter in a solution con taining sodium hydroxide and ammonia.Following this, the material was thoroughly washed in a bath of diluteammonium hydroxide to remove any dissolved material. The material wasthen treated in a 5% solution of sulphuric acid to remove any trace ofcopper and finally rinsed 7 and dried to constant weight to determinethe loss due to dissolving of the lesser celluloses and impurities. Thecorrelations of the quantities of reagents used (concentrations), withrespect to each other, and with respect to the quantity of materialbeing treated (expression) are shown in the following table:

method herein described shows substantially no shrinkage in warp or weftdirections when subjected to repeated launderings, and also retains thelustre and other desirable'qualities received during the treatment.

The invention will be readily understood from the following examples inwhich certain preferred methods of employing the invention are given,illustrating the range of concentrations of the reagents that may beemployed in treating various fabrics, threads, and yarns. Figures andratios are quoted in terms of copper sulphate (CUSOH2O) for the sake ofconvenience; the matter of applying the ratios and concentrationsaccording to their copper equivalent in the other water-soluble coppersalts is merely a matter of simple calculation; the same applies to theapplication of the figures quoted for sodium hydroxide to other alkalihydroxides, or mixtures of such hydroxides.

Since the quantity of water-soluble copper salt contained in the fibresdetermines the ultimate degree of treatment, it is this part of theprocess that is the most critical and which requires the greatest amountof control. There are a great many different types of cellulosicmaterials in the form of fabrics and yarns, etc., and thus havingdifferent weights per square yard, and we have discovered that there arecertain critical copper to cellulose ratios governing the maximumquantity of water-soluble copper salt held in and on the fibres of thevarious Weight per square yard materials above which dissolvedalpha-cellulose is liable to result. In practicing our invention it ishighly undesirable that any alphacellulosebe dissolved and precipitatedon a fabric or yarn; furthermore, the formation of a film of dissolvedcellulose on a fabric or yarn inhibits the treatment of the interior ofsuch material since such a film insulates the material and is ratherdiflicult to penetrate. The copper/ammonia processes known to usadmittedly treat Table 1 Material treated 0 so 5H 0 N on NB Dres- 33.LOSS in 1 a sion weight aria/litre Gma/iitra G'IflS-l/itffl Percent C..Pe'rce'nt Indian head brOWIL 247. 8 78. 3 137. 18 67 24 1. 31 equ 247.8 78. 3 137. 18 80 24 1; 16 Indian head brown.. 154 47. 2 164 95 24 l.01

material other than the lesser celluloses is avoided.

A feature of the invention is the provision of a method of treatingcellulosic yarns, threads, fabrics and the like, to make themsubstantially .unshrinkable in laundering; that is, thematerial willsubsequently retain the dimensions set therein during treatment. It hasbeen found that the dimensions of the material can be stretched up to24% of any one dimension or up to 12% of both dimensions, in the case offabrics, during treatment and accordingly that the original or desiredarea will be retained when the material is subjected to the customarywashing. Cellulosic material treated in accordance with the only thesurface of the exterior fibres by dissolving these surface fibres,relying upon speed and the squeezing out of most of the dissolved alphaicellulose to minimize the damage to the material being treated. A numberof these prior art processes deal with a mixture of the three essentialingredients into a single highly active solvent solution, i. e., thecopper salt, the sodium hydroxide, and the ammonium hydroxide, which hasthe effect of mass action on the surface of the fibres of the materialbeing treated.

A particular feature of our process is that it is possible thereby toobtain the maximum of desirable treatment of all the fibres in thematerial and the interior of the fibres without dissolvingalpha-cellulose. We have discovered that the normal tendency of a fabric(or fibres in the form of bundles of yarn such as warps or skeins) toretain trapped excess copper salt solution, likely to cause dissolutionof the alpha-cellulose, increases 1 with the fabrics weight per squareyard; accordingly, an important feature of our invention is thediscovery of a range of copper to cellulose ratios for the variousweight per square yard fabrics below which alpha-cellulose will not bedissolved and wherein we are able to obtain the maximum degree oftreatment without fear of dissolved alpha-cellulose in the localportions where this excess copper salt is retained. In this way thereaction is always under control since it Table 3 The decimal figures inthis table represent the copper (CuSO4.5H2O) to cellulose ratios withrespect to the copper sulphate concentration and the percentum of coppersulphate solution remaining in the material, after removal of excess,

cannot proceed beyond the point determined by based on the original dryweight of such material the quantity of copper salt present in and oneach (expression).

flg 110% 105% 100% 05% 85% 20% 15% 10% g .2848 .2112 .2510 .2440 .2505.2110 .2054 .1898 .1152 .2112 .2540 .2508 .2215 .2244 .2112 .1950 .1848.1115 .2005 .2551 .2420 .2110 .2152 .2054 .1225 .1101. .1668 2618 24932368 2244 2119 1994 1870 1745 1520 .2540 2419 2298 2177 2056 1935 18141693 1572 2461 2344 2227 2110 1992 1875 .1758 1641 1524 2381 2268 21552041 19% 1814 1701 1587. 1474 2302 2192 2082 1973 1863 1754 1644 15341425 2%)7 2115 2009 1904 1798 1692 1586 1480 1375 2138 Z136 1934 18321731 16%) 1527 1425 1323 .2056 1958 1860 1762 .1664 1566 1468 1371 12731972 1878 1784 1690 1596 1502 1109 1315 i221 .1888 .1102 110a .1512.1522 .1438 .1245 .1259 1100 fibre in the fabric when it comes intocontact The ratios for solutions below 200 grams per with the alkalihydroxides.

The following is a table of the copper expressed in terms of CuS045H2Oto cellulose ratios ior various fabrics of differing weight per squareyard. The ratios so expressed are the upper limits which we desire toemploy at room temperatures, such as approximately 20 C. or higher inthis method, after the material has been immersed in the copper saltsolution; excess CuSO4.5H2O solution above this ratio should be removedfrom the material before it is subject to treatment in the otherreagents.

It will be seen from the foregoing table that the copper to cellulose,in terms or copper sulphate, ratios increases .01 for each added squareyard per pound or fabric; thus marquesettes, which are about 15 squareyards to the pound, would havea preferred limiting ratio of .3.

The above table represents the upper limits for each type of materialwhich has been kier boiled, malted, and/or bleached, irrespective-of theconcentrations of the ammonia and other alkali hydroxides, ortime ofimmersion. If the fibres or material are in the unbleached or greystate, slightly higher concentrations of the water-soluble copper saltmay be employed to produce a similar finish without dissolving alphacellulose.

The highest practical concentration of copper sulphate solution in termsof grams per litre and expression (percentum of copper sulphate solutionremaining in the material after removal or theexcess solution based onthe original dry weight of such material) for any oi! the ratios 'setforth in Table 2 can readllybe determined from the following, Table 3:

litre can readily be calculated.

For example, if the highest concentration of copper sulphate solutionthat may be employed on a 6 square yard per pound material is to bedetermined, it will be noted in Table 2 that the maximum ratio is .21,and from Table 3 it will be noted that 320 grams per litre coppersulphate solution maybe employed at 75% expression, or a 300 grams perlitre solution may be employed at expression. The ranges of coppersulphate concentration which may be employed for various materials,depending upon the type of finish desired, will be apparent fromExample 1. However, in no case is it desired to exceed the ratios setforth in Table 2. It is not deemed practica1 or feasible to employexpressions, even with more dilute solutions of copper sulphate, above110%. with some fabrics it is not practical to employ expressions as lowas 65% and in many cases this will depend upon the apparatus available;however, from Table 3 it is apparent that higher expressions may readilybe employed with a lower concentration of copper salt solution. Forinstance, in the illustration given employing 6 square yard per poundmaterial, if the apparatus available is not adapted to supply an evensqueeze at 75% expression, the method can be employed at expression withapproximately 235 grams per litre copper sulphate solution.

In a slightly modified method, by controlling the temperature, time ofimmersion, and the concentrations of the alkali hydroxides, coppersulphateto cellulose ratios somewhat higher than those of Table 2 maybeused, without dissolution of the alpha cellulose. These higher ratiosmay go as far as an extra .05 of C.uS04.5H2O to cellulose for each ofthe various weight fabrics. This may be determined in the followingmanher, which covers the whole range of concentra-.

jproportions will cause a corresponding reduction in the total reaction;further, it the time is insuflicient for a selective'absorption of thereagents from a solution in whose total volume more than molecularproportions are present but in a dilute form, the reaction'will not goto for each increase of .01 in the copper sulphate to cellulose ratioabove the limits in the foregoing Table 2 (up to .05 in the case of eachweight fabric), the concentration of each alkali hydroxide solution mustbe reduced by 10% below molecular proportion concentrations with respectto the copper salt concentration, and the time of immersion must notexceed three seconds. The most effective molecular proportions being:

CuSO45HzO-1 11161 (249.71) or in parts 1. NaOH 2 mols (80.02) or inparts 0.32

4 mols (68.12) or in parts 0.273

upon which this modified method is based.

The efiiciency of the reaction increases with an increase in the NHsconcentration and/or a decrease in the temperature of the hydroxidesolution. However, it is not necessary to have the ammonia concentrationabove 8 mols at room temperature, and 4 mols is preferred. For thepurpose of economy, refrigeration may be used in the alkali solution sothat proportions below 8 mols of ammonia may be used, with the resultantsaving in ammonia. Thus, where 8 mols of NH3 may be used at roomtemperature of approximately 20 C., l mol of NH3 may be taken off theammonium hydroxide concentration for each. drop of C. in the temperatureof the hydroxide solution. We prefer to use refrigeration in theammonium hydroxide-alkali hydroxide solution only when the materialbeing treated is well below the copper to cellulose ratio limitspreviously set forth.

It is believed that the invention will be readily understood from theforegoing description and ratios in conjunction with the followingspecific examples which are illustrative of our improved method.

Example 1 A light fabric, such as a lawn having a count of threads perinch, both warp and weft, of 68x72 or- 88x80, which is approximately 10square yards to the pound in the malted and kier boiled and/or bleachedstate, is led into a solution of copper sulphate and thoroughlyimpregnated, and

then it is led through squeeze rolls into a solution of ammoniumhydroxide and sodium hydroxide and squeezed again through rolls toremove excess.

A. For a soft to a slightly crisp finish, the CuSO45HzO concentrationmay be up to 150 grams per litre. NaOH concentration up to 48 grams perlitre, and N113 concentration up to 82 grams per litre.

B. For a slightly crisp to a crisp finish, the CIISO45H2O' concentrationmay be from 150 grams to 230 grams per litre. NaOH concentration up to'74 grams per litre, and NH: concentration up to 126 grams per litre.

C. For a crisp to a very crisp or organdy-like finish, the CuSO45H2Oconcentration may be from 230- grams to 320 grams per litre, NaOHconcentration up to 104 grams per litre, and NH3.

concentra ion up to 185 grams per litre.

The percentage of copper sulphate solution remaining in the evenlysqueezed fabric after the first step should be below 110% of the weightof the fabric in A and B and, in order to eliminate the possibility ofdissolved. alpha cellulose, with 320 grams per litre copper sulphate inC, the percentage remaining should be below 93%.

The higher copper salt concentration apparently prepare the cellulosefor a new and distinct action by caustic alkali of mercerizing strength(that is, between 200 and 450 grams per litre NaOH) in such a way that,the fibres having been deflated after the swelling action of the causticalkali by the usual souring, washing and drying operations, they arecondensed in such a way as to make them crisp and to retain theircrispness even after repeated launderings.

Forthis reason, when crisp finishes are required, we prefer to lead thefabric directly into caustic alkali of mercerizing strength after itleaves the squeeze rolls from the caustic/ ammonia solution, and thenceonto a mercerizing machine. While we have successfully treated thefabric without tension while it contained the caustic alkali, however,we prefer to use tension in this step such as that obtained on any ofthe standard mercerizing machines. The alkali may be removed from thecloth with water after mercerizing and then the cloth may be soured in asuitable acid such as sulphuric acid, and then washed again to removethe acid.

Thus, the process may be carried out successfully and efiiciently byplacing two extra boxes, fitted with adequate squeeze rolls, in tandemwith the caustic alkali box on any of the standard mercerizing machines,and the whole process may be carried out continuously.

A certain degree of stiffness or crispness may be obtained by finishingup (that is, washing and souring, washing and drying) the fabric afterthe caustic/ammonia treatment when the higher concentrations of coppersalt solutions are used. This, we believe, is because the lessercelluloses and other impurities, which are probably in theinter-micellular spaces as well as the core of the fibres, are moreefliciently removed, and upon drying the alpha cellulose micells in eachfibre become more intimately in contact with each other due to theattendant reduction in the diameter of the fibre, However, when thefibres come into contact with strong caustic alkali after thecaustic/ammonia step they are in an excellent condition for the swellingaction which then takes place, thus, upon deflation with water, souring,washing and drying, they are able to still further deflate themselves,closing in on the spaces left by the removal of the impurities, so thateach fibre is apparently a more condensed and homogeneous mass of alphacellulose of smaller diameter; the result being that a. beautifullysheer, crisp, and lustrous fabric is obtained, and one which takes dyesdefinitely deeper and better than a fabric which has merely beenthoroughly mercerized and bleached in the usual manner.

The application of the method to other weight fabrics is readilyapparent from the foregoing example in conjunction with the ratiosexpressed on page 3.

Example 2 In a slightly modified method the cellulosic fibres are wettedwith a copper sulphate solution (CuS04.5H-2O) of approximately 158 gramsper litre, and centrifuged. or squeezed until the remaining material isapproximately double the weight of the original dry mass. The fibres maythen be introduced into an ammonium hydroxide and sodium hydroxidesolution of approximately grams of NH; per litre and 50 grams of NaOHper litre and are then stretched and introduced into a solution ofsodium hydroxide of approxi- .alkalies and dissolve the copper.

is then washed with hot or cold water until free of alkalinity.Thereafter the fibres are first washed in a dilute solution of sulphuricacid, for example, 60 grams per litre, and again washed in a solution ofsulphuric acid of approximately 25 grams per litre. The acid is thenremoved by washing in water and the fibres dried in any suitablefashion, for example, by air, 7

In order to be set in such a wayas to render the fabric substantiallyunshrinkable, the second mentioned treatment with sodium hydroxide ismade when the fabric is in a stretched condition. Therefore, the fabricis preferably stretched warpwise and fillingwise between and 12 abovethe original grey sizes or the-material may be stretched in any onedirection up to 24% of its original dimension, immediately after it hasbeen treated in the ammonia-caustic soda.- solution, at which time itisin a somewhat plastic condition and may therefore be more easilystretched both weftwise and warpwise to a point greater than itsoriginal size.

It is not necessary to remove the alkali hydroxides nor the copperbefore the subsequent treatment with sodium-hydroxide. The treatment forshrinkproof qualities preferably requires that the alkaline hydroxidesbe removed while the cloth is in a stretched condition in order to setthe desired dimensions; they may be removed by either washing withwater, by

- phate neutralizing, or both. In the interest of economy it isdesirable that most, if not all, of the alkali hydroxides beremoved withwater, thus enabling them to be easily recovered by well-known methods,such as by evaporation.

It should be noted that the dimensions of the cloth at the time thesodium hydroxide is applied do not remain after the tension is reduced,the fabric is stretched to a definite excess stretch (depending upon thecondition of the cloth, and type of cloth, and the desired finisheddimensions). For example, if the grey dimensions are desired in thefinished goods, the cloth is treated in the grey State and stretched toapproximately 11%% greater than its grey measurement both warpwise andweftwise before treatment with the sodium hydroxide, and this excessstretch is maintained until the fabric has been freed of the alkalinehydroxides.

Example 3 ed to reduce the surface tension of cotton fibres.

After the fibres are wetted. the excess copper sulphate solution and thewetting agent are removed by an air blast or centrifuging, until theexpression of copper solution remaining on the fibres is approximately100% of the dry weight of .the fibres, the fibres are treated with asolution containing ammonium hydroxide and sodium hydroxide having areduced caustic alkali content so as to inhibit the swelling andshrinking of the fibres. The fibres are again dried and introduced intoa dilute sulphuric acid solution of about 60 grams of acid per litre toneutralize the The fibres are again washed in a weak solution ofsulphuric acid of about grams of acid per litre to complete the removalof the copper. Thereafter, the treated material may be washed with waterto remove the acid, and dried. A copper sulsolution containing 76 gramsof CuSO4.5H-.-O per litre is satisfactory, and the ammonium hydroxideand sodium hydroxide solution may contain 68 grams of NH: per litre and7 grams of NaOH per litre. If a wooly fibre is desired, the abovespecified concentrations may be increased."

, Example 4 This modification contemplates treating cellulosic textilefibres in such manner that their hot flexing life and hot tensilestrength is notably increased. In this method, fibres are firstsaturated with a solution of copper sulphate and then in a solution ofammonium hydroxide and sodium hydroxide; the concentrations of saidsolutions and the time of treatment are such that the impuritiesvin thecellulosic fibres such as sugars,

glucosides and the like, are substantially completely dissolved andremoved from the fibres. The cellulosic textile fibres are then freed ofthe copper and alkaline hydroxides in dilute acid baths and the fibreswashed in water, and if they are in a combined form, dried under tensionto the desired dimensions. Satisfactory results have been obtained whenthe CllSO4.5H2O to cellulose ratio is- .25 to 1, and, after the excesscopper sulphate has been removed, the copper solution remaining in thefibres not exceeding their original dry weight by more than 110%, theC11S04.5H2O to NaOH ratio on the fibres is 1 to .32. The NHa content mayvary from 80 to 132 grams per litre. The treated cellulosic fibres arethen washed, first in a dilute sulphuric acid bath of about 60 grams oracid to neutralize the hydroxides and to dissolve the copper, andin a'second acid bath of about 25 grams of sulphuric acid per litre. The acidis then removed by washing in water and the fibres dried under tensionto the desired. dimensions.

Example 5 This modification contemplates treating cellulosic textilefibres in such a manner as to increase the tensile strength both at lowand high temperatures and to improve their appearance and absorption ofdyestuffs. More particularly we have in mind the treatment of fibreswhether in any of the various stages prior to baths, and the fibreswashed in water. In the phate containing 158 grams of copper sulphate-(ousoasrnm per litre, the excess solution being removed by well-knownmethods such as squeezing through nip rolls or centrifuging until thecopper sulphate ratio to cellulose is below .145 and the residualsolution in the fibres is not in excess of approximately 100% of the dryweight of the material being treated; and then treated in a solutioncontaining 100 grams of ammonia (NHa) per litre and 30 grams of sodiumhydroxide (NaOH) per litre.

It is to be understood that the foregoing examples setting forthspecific materials, weights and proportions, are given for the purposeonly of illustrating the invention, and that our invention is notlimited thereto but contemplates such other and further modificationsand changes which may become apparent to those skilled in the art andwhich are inherently possessed herein. It is now believed that indescribingthe operation of our invention, and the delineation of theexamples, the same has become thoroughly apparent as well as the newproducts resulting therefrom.

We claim:

1. The method of treating cellulosic textile material to selectivelydissolve and remove therefrom the lesser celluloses, sugars, glucosidesand other impurities without dissolving the alpha cellulose contentthereof, which comprises the steps of first thoroughly impregnating thematerial with a solution of a. water-soluble copper salt,

removing excess copper salt solution from the material so that thequantity of the copper salt remaining on the material does not exceed,in terms of CHSO4.5H2O, 1 part of copper salt to 4 parts of cellulosicmaterial for average lightweight materials such as those weighing 1pound per square yards, with proportionately smaller ratios of coppersalt for heavier materials the ratio of copper sulphate to cellulosebeing reduced .01 in heavier fabrics for each lessened square yard perpound of material being treated, then treating the material in asolution of ammonium hydroxide and an alkali metal hydroxide having abasicity greater than ammonium dissolving the alpha cellulose contentthereof, which comprises first thoroughly impregnating the material in asolution of copper sulphate, removing excess solution from the materialuntil the ratio of copper sulphate to cellulose is such that alphacellulose" will not be dissolved upon subsequent treatment, for fabricscomprising one square yard per pound the ratio of copper sulphate(CUSO45H2O) to cellulose being not in excess of .16, said ratioincreasing .01 for each added square yard per pound of cellulosicmaterial, then treating the impregnated material in a solutioncontaining ammonium hydroxide and an alkali metal hydroxide having abasicity greater than ammonium hydroxide, and then washing the materialto remove the reagents and dissolved impurities.

4. The method of treating cellulosic textile material to removetherefrom the lesser celluloses, sugars, glucosides and other impuritieswithout dissolving the alpha cellulose content thereof, which comprisesthe steps'of first thoroughly impregnating thematerial in a solution ofcopper sulphate, removing excess solution from the material until theratio of copper sulphate to cellulose is such that alpha cellulose willnot be dissolved upon subsequent treatment, for'fabrics comprising onesquare yard per pound the ratio hydroxide, and finally washing thematerial to remove the reagents and the aforesaid selectively dissolvedimpurities.

2. A method of treating cellulosic textile material to remove therefrom,the lesser celluloses, sugars, glucosides and other impurities, withoutdissolving the alpha cellulose content thereof, which comprises firstthoroughly impregnating the material in a solution of copper sulphate,the concentration of the copper sulphate solution retained in thematerial being varied in accordance with the character of the materialunder treatment, a relatively high concentration 'kali metal hydroxide,the quantity of alkaline hydroxide other than ammonium hydroxideemployed preferably being in the ratio of at least approximately 1 partof alkaline hydroxide to 3 parts of copper sulphate on the material, andfinally washing the material to remove the reagents. e

3. The method of treating cellulosic textile material to removetherefrom the lesser celluloses, sugars, glucosides and other impuritieswithout of copper sulphate (CllSO45H2O) to cellulose being within therange of .16 to .21, the range of said ratios increasing .01 for eachadded square yard per pound of cellulosic material, then treating theimpregnated material for a period not exceeding three seconds in asolution containing ammonium hydroxide and an alkali metal hydroxidehaving a basicity greater than ammonium hydroxide, the concentration ofthe alkaline solutions being reduced 10% below molecular proportionswith respect to each .01 increase in the copper sulphate to celluloseratio based on the ratio of .16 for fabrics comprising one square yardper pound and the increased ratio for lighter fabrics, and then washingthe material to remove the reagents and dissolved impurities.

5. The method of treating cellulosic textile material to removetherefrom. the lesser celluloses, sugars, glucosides and otherimpurities without dissolving the alpha cellulose content thereof, whichcomprises first impregnating the material in a solution of coppersulphate, removing excess solution from the material until the ratio ofcopper sulphate to cellulose is such that alpha cellulose will not bedissolved upon subsequent treatment, for fabrics comprising 1 squareyard per pound, the ratio of copper sulphate (CuSO45H2O) to cellulosebeing below .16, saidratio increasing .01 for each addedsquare yard perpound of cellulosic material, then treating the impregnated material ina solution containing ammonium hydroxide and an alkali metal hydroxidehaving a basicity greater than ammonium hydroxide, the ammonia (Nm)concentration being 8 mols of ammonia to 1 of copper sulphate atsolution temperatures of approximately 20 C., the concentration ofammonia being reduced 1 mol for each 5 0. reduction in solutiontemperature from 20 C'., and then washing the material to remove thereagents and dissolved impurities.

6. The method of treating cellulosic textile material to improve thequality thereof and to render it substantially unshrinkable, whichcomprises thoroughly wetting said material in a solution of awater-soluble copper salt of a con centration inadequate to cause thedissolution of the alpha cellulose during the treatment, but suiiicientto remove the lesser colluloses such as sugars glucosides and otherimpurities; removing the excess solution from said material so that forfabrics comprising one square yard per pound the ratio of copper salt tocellulose is not in excess .16, said ratio increasing .01 for each addedsquare yard per pound of cellulosic material, and then subjecting thematerial to the action of-a solution of ammonium hydroxide and dilutesodium hydroxide, stretching the material to the desired dimensions upto 24% of any one dimension or up to 12% of both dimensions, and thensubjecting said material to the action of a solution of sodium hydroxideof a mercerizing concentration, washing said material in water to removethe 'alkalies, then removing the tension on said material, and thenwashing said material in a dilute acid solution to remove copper,thereby recovering said reagents.

7. I'he method of treating cellulosic textile material to removetherefrom the lesser celluloses,

sugars, glucosides and other impurities without dissolving the alphacellulose content thereof, which comprises first thoroughly impregnatingthe material in a solution of copper sulphate, removing excess solutionfrom the material until the ratio of copper sulphate to cellulose issuch that 'alpha cellulose will not be dissolved upon subsequenttreatment, for fabrics comprising one square yard per pound the ratio ofcopper sulphate (CuSO45HzO) to cellulose being not in excessof .16,theconcentration of the copper sulphate solution being not in excess ofapproximately 285 grams of CuSO45H2O per litre, said ratio increasing.01 and the maximum permissible concentration of copper sulphatesolution also being increased for each added square yard per pound ofcellulosic material, then treating the impregnated material in asolution containing ammonium hydroxide and an alkali metal hydroxidehaving a basicity greater than ammonium hydroxide, and then washing thematerial to remove the reagentsand dissolved impurities.

8. The method of treating cellulosic textile material to removetherefrom the lesser celluloses, sugars, glucosides and other impuritieswithoutdissolving the alpha cellulose content thereof, which comprisesfirst thoroughly impregnating the material in a solution of coppersulphate, removing excess solution fromthe material until the ratio ofcopper sulphate on the material to cellulose is such that alphacellulose will not be approximately 285 grams of CuSO45HzO per litre,

said ratio andthe maximum permissible concentration of copper sulphatesolution being increased relatively for lighter weight fabrics saidratio being increased approximately .01 for each additional square yardof material per pound,

WILLIAM A. BODENSCHATZ. ERIC OW'EN' RIDGWAY.

